blender immediately shuts down my computer whenever cycles renders anything
TL;DR:
it was a bios setting that by default, shut down the computer when you tried to use it
full version:
I did end up finding the issue, but its what I least expected. to, in the bios on my mobo, you can control the current going through the VRM's, you can adjust it in percentage so that if it goes over a certain percentage, it'll enter a shutdown state and reset. mine was set to 35%, of the total allowed current draw, so it would shut down if it went over that. I was measuring different points on the motherboard, and I noticed that the shutdown on the VRM controller was being triggered, but there was no voltage drop, (which would mean its a power supply) so I went into bios and I found probably the most annoying default bios setting I've ever dealt with, the current shutdown limit, mentioned above.
my full setup, for anyone else having this issue:
ASUS TUF gaming+wifi x570 running the second latest bios as of 8/12/20 (all stock settings
aside from the boot order)
3900x, stock clocks with a 240mm AIO
1080ti founders edition, stock clocks
32 GB 3200MHz DDR4 corsair vengeance
Seasonic 900 watt PSU
3 HDD's, an ODD, and an M.2
running windows 10 home edition x64 fully updated as of 8/6/20
Blender version 2.83
latest Nvidia drivers as of 8/11/20
steps to create the issue:
render anything using the cycles render engine using the CPU.
steps to solve the issue:
adjust bios settings, specifically under advanced&lt;DIGI+ VRM&lt;current shutdown, from 35% to 100%. another thing that may have worked is flashing on the latest bios, or re-setting everything to defaults, but I don't recall changing this setting, so it may be a bug in this bios rev, IDK, but this fixed my issues. hope it helps :)
P.S.  sorry for the information overload, but I figure if anyone else has this problem, too much info is better than not enough info.